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Put new air filter in and now surging in powerband?

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Hey y'all, I serviced my bike the other day by changing the oil, new air filter etc. and now when I'm topped out it surges almost like I'm hitting a rev limiter of some sort? Basically it's going in and out of power band like a pulsing. I checked the PV and it all looks good and the cables are properly adjusted etc. Any thoughts on what this could be? Bike was running amazing before the service. Plug is cardboard brown but the bike is spooging quite a bit now as well. Any help would be greatly appreciated. :busted:

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Had the same prob on my CR80.

The reason is because the filter is to restrictive, or over oiled. I threw a notoil in and it fixed it.

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Well I put the old filter back in and it's doing the same thing... I changed the plug as well and still no change. Kind of at a loss here and am starting to get frustrated. Is there any way that my power valve is out of time or something? The bike starts perfectly and the entire throttle range is great until I'm at full throttle and it starts to cut in and out. The rear tire spins every time it pulses like it's going in and out of powerband.

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pull your jets and clean them. the only connection i see between cleaning the air filter and the pulsing, is dirt. you may have dropped some dirt into the boot and it may have worked it way in/around the carb and worked its way into the jets. it certainly sounds like a stretch to get dirt to clog the main or pilot from that direction instead of from inside the bowl, but this is a quick and free check and certainly suspect. weirder shit has happened.

once you have that squared away, if the problem remains you can start a more thorough diagnosis.

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Well, it'll run lean with a dirty air filter or a over-oiled one. I don't see how a bike that's running fine before a service isn't some how the filter. You didn't put a paper towel in there, did you? Sometimes I guess they just start running poorly because they feel like it.

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Did you change octane or oil ratio at all? Sometimes bikes will react way different if it's not the same stuff...I'd make sure the filter isn't over oiled like the one guy already said...Then get started on the jetting...

Although if it's not the filter it likely could be the jetting because the winter is when bikes start to go lean and you have to richen them up and vice versa in the summer so maybe you need to bump up on your main jet. Check your tuning chart in your manual and see what it says you should be at @ your altitude and current temp range.

My tuning chart calls for no changes but a quarter turn richer on the air screw and a 178 main vs. a 175 that's in it now! Surging is a classic sign of lean from what I understand, but spooge is a sign of being rich...I'm still learning and get confused by these things all the time but I'd bet the bike is going lean with the temp dropping if it ain't the filter! I know it started right after a service but honestly when adjustments need to be made on these things they always start running funky out of the blue so maybe it just so happened to be after a service??? Just a thought. I mean, it's gotta happen sometime right? Have you gone through any major temp/altitude changes wherever you're at?

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Haven't changed the oil, oil ratio or gas. It's the same can I went to the track with a few weeks ago and the bike ran like a champ. Octane is the fuel's ability to resist auto ignition and shouldn't affect the way the bike runs unless it's rating is super low which it isn't since I bought 91 and it's only a few weeks old. I sonic cleaned the carb at work but it didn't need it since I had done a few months back and was clean and all circuits were free flowing. I will check the jetting next but what has me puzzled is the fact that the bike is spooging and the plug is dark brown. I'll report back with what I find... Maybe it's the servo motor taking a dump and just happened to be just after the filter change?

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